On the Value of I'uison Bait for Controllinj5 Cane (iriibs. 



Poisoning the Soil. 



Gni])s placed in moist eartli containing aceto-arsenate of coiii^er in 

 the ]n'oportion of 2 oz. to one cubic foot (infected by thoroughly mixing 

 the (h-y poison witli sifted soil) remained normal tlirougliout the course 

 of tlu'se experiments, while the same chemical administered at tlie rate 

 of 8 oz. to a cubic foot was (juickly fatal to 100 per cent. London jniri^le 

 (8 oz. to 1 foot) proved effective, but less deadly tlian the foregoing 

 arsenical. Carbide lime, sulphur, and several other chemicals gave 

 negative results. This mode of application appeared out of the question 

 owing to excessive cost of both labour and materials, so further research 

 was postponed, pending the possible discovery of a more suitable sub- 

 stance possessing mannrial i)roperties. 



POISON BAIT AS A MEANS OF CONTROL. 



The great importance of experimentation in this connection was 

 recognised from the start and kept in view throughout the course of the 

 above-mentioned preliminary research work initiated last year, wliich, in 

 fact, served as a stepping-stone to more extended investigations. 



(^ur cane grub being voracious in appetite, and what is termed a 

 gross fi'eder, it seemed highly probable that it would swallow almost 

 any kind of poist)n providing its odour was not obnoxious and the bait 

 used sufficiently attractive. Later experiments, to be touched on pre- 

 sently, amply demonstrated the correctness of this assumption. 



The first step was to discover some vegetable substance that, whilst 

 not (luickly decomposing when buried in the soil, would at the same 

 time be palatable throughout a ])eriod of three weeks or longer, either in 

 a fresh form or as vegetable humus. In addition to the foregoing 

 qualifications, this desirable substance ha<l, above all, to be cheap, readily 

 obtainable in bulk, and easy to apply. 



As a result of numei-ous ex])eriments it was found that lai-vie of our 

 .Mcaly-ltack Cane Beetle would eat many kintls of roots, &c., and weiv 

 apparently very partial to the tubers of both English and sweet potatoes, 

 cucumber skins, and thin slices of cane stalks sectioned transversely. 



In May. 191"), whilst watcliing some plougliing operations on land 

 tiial had i-eceiitly been green matuired, it suddenly occunvd to iiie tint 

 here. perhai)s, was the key to the situation— viz.. the employment of 

 either Mauritius bean or eo\v-j)ea as a bait, which, in addition to the 

 possession, possibly, ol' ail the a!)ove-mentioned requii'ements woidd act 

 also as a manure, and so hel[) t<> redui-e the expense of application. 



